Change:

            double toysCnt = puzzelCnt + bearsCnt + minionsCnt + truckCnt;

to:

            double toysCnt = puzzelCnt + bearsCnt + minionsCnt + truckCnt + dollCnt;

;-)

Code =>

using System;
using System.Transactions;

namespace Toy_Shop
{
    internal class Program
    {
        static void Main(string[] args)
        {
            double excursionPrice = double.Parse(Console.ReadLine());
            int puzzelCnt = int.Parse(Console.ReadLine());
            int dollCnt = int.Parse(Console.ReadLine());
            int bearsCnt = int.Parse(Console.ReadLine());
            int minionsCnt = int.Parse(Console.ReadLine());
            int truckCnt = int.Parse(Console.ReadLine());


            double puzzelPrice = puzzelCnt * 2.60; 
            double dollPrice = dollCnt * 3; 
            double bearsPrice = bearsCnt * 4.10;
            double minionsPrice = minionsCnt * 8.20;
            double truckPrice = truckCnt * 2;


            double totallPrice = puzzelPrice + dollPrice + bearsPrice + minionsPrice + truckPrice;
            double toysCnt = puzzelCnt + bearsCnt + minionsCnt + truckCnt + dollCnt;


            if (toysCnt >= 50)
            {
                double discount = 0.25 * totallPrice;
                totallPrice -= discount ;
            }
            double rent = 0.10 * totallPrice;
            totallPrice -= rent;
            if (totallPrice >= excursionPrice)
            {
                double moneyLeft = totallPrice - excursionPrice;
                Console.WriteLine($"Yes! {moneyLeft:F2} lv left.");
            }
            else
            {
                double moneyNeed = excursionPrice - totallPrice;
                Console.WriteLine($"Not enough money! {moneyNeed:F2} lv needed.");
            }
        }
    }
}

Alternative =>

using System;
 
namespace ShopForKids
{
    internal class Program
    {
        static void Main(string[] args)
        {
            double vacationPrice = double.Parse(Console.ReadLine());
            int puzzles = int.Parse(Console.ReadLine());    
            int talkingDolls = int.Parse(Console.ReadLine());
            int teddyBears = int.Parse(Console.ReadLine());
            int minions = int.Parse(Console.ReadLine());
            int trucks = int.Parse(Console.ReadLine());
 
            double puzzlesPrice = puzzles * 2.6;
            int talkingDollsPrice = talkingDolls * 3;
            double teddyBearsPrice = teddyBears * 4.1;
            double minionsPrice = minions * 8.2;
            int trucksPrice = trucks * 2;
            
            double toysTotal = puzzles + talkingDolls + teddyBears + minions + trucks;
            double totalPrice = puzzlesPrice + talkingDollsPrice + teddyBearsPrice + minionsPrice + trucksPrice;
 
            if (toysTotal >= 50)
            {
                double earnedMoney = totalPrice - (totalPrice * 25 / 100);
                double moneyForRent = earnedMoney * 10 / 100;
                double totalEarned = earnedMoney - moneyForRent;
                double moneyWithVacation = totalEarned - vacationPrice;

                if (totalEarned >= vacationPrice)
                {
                    Console.WriteLine($"Yes! {moneyWithVacation:f2} lv left.");
                }
                else if ( totalEarned < vacationPrice)
                {
                    double neededMoney = vacationPrice - totalEarned;
                    Console.WriteLine($"Not enough money! {neededMoney:f2} lv needed.");
                }
            }
            else if (toysTotal < 50)
            {
                double moneyForRent = totalPrice * 10 / 100;
                double totalEarned = totalPrice - moneyForRent;
                double moneyWithVacation = totalEarned - vacationPrice;

                if(totalPrice >= vacationPrice)
                {
                    Console.WriteLine($"Yes! {moneyWithVacation:f2} lv left.");
                }
                else if (totalPrice < vacationPrice)
                {
                    double neededMoney = vacationPrice - totalEarned;
                    Console.WriteLine($"Not enough money! {neededMoney:f2} lv needed.");
                }
            }
        }
    }
}